Interactive resource
Unit Circle: sin, cos, tan Visualizer
Trigonometry. Drag an angle on the unit circle to see (cos θ, sin θ) and tan θ — ideal for introducing trigonometry. Free interactive GeoGebra resource —…
Overview
The unit circle links angles to coordinates: the terminal point is cosine and sine. Dragging beats memorizing alone.
Explanation
The unit circle is centered at the origin with radius 1.
Angle θ meets the circle at P(cos θ, sin θ).
tan θ = sin θ / cos θ (signed height at x=1).
Identity: sin²θ + cos²θ = 1.
How to use
- Open the unit-circle scene.
- Drag the angle slider.
- Read cos, sin, and tan.
- Check that sin²θ + cos²θ = 1.
Classroom tip
Start in quadrant I, then move to quadrant II to see positive sine and negative cosine.
Knowledge points
FAQ
Do students need radians first?
Degrees work fine for intuition; radians appear alongside.
Is this tool free?
Yes. It runs in the browser with no install.
Good for class demos?
Yes — project it and ask what changes when you drag a parameter.
How do I write the formula afterward?
Open the equation editor or symbol sheet and copy a clean expression.